Next Mastery to unlock - Glass Cannon; Despair; Coagulate; Inequity or Willpower?

winterthur

Getting another mastery point soon and wondering which to unlock.

I already has a point in Willpower and reading opinions, seems that should be it.
Looks like either Inequity or Despair should be next since it costs more to unlock compared with the other two ( my simple thinking ).

Also, I don't quite understand what is meant by "for each detrimental effect". Is this the same as debuffs?

Any suggestion and some explanation?
Thanks.

slipkrash

I would unlock despair next. After that, deep wounds, then assassin.